article: Top student Lin Yijian had a problem recently. The 14-year-old boy from Xiamen used to get marks of over 110 points (out of 120 possible points) on his math tests. But during last semester's final exams, his math score was only 90 points.
  It was a shock. "I didn't know what happened," said Lin, who kept feeling nervous and frustrated about math during the following month.
  Like Lin, many of us have setbacks   in life. What would you do to deal with these setbacks? Would you just let them be and give up?
  Lin chose to face his problem. His parents and teacher also gave him help. After some hard work he now gets marks between 100 and110 points on his math tests. Although he still isn't at his original   level, Lin doesn't panic anymore.
  "Don't be scared by setbacks," he said. "You will beat it."
  Chen Xingzhu in Shenzhen also has a story to tell. The 15-year-old girl is not good at doing sit-ups  , which is necessary for the coming high school PE entrance exam. One has to do at least 35 sit-ups in a minute to pass the test. Most of Chen's classmates can do 40. However, Chen could only do 20.
  Feeling worried, Chen decided to do something. She did sit-ups for half an hour every day after school. Now, after a month, she can do 30 sit-ups a minute.
  "I finally found what made me slow through continuous practice and then improved little by little," said Chen. "I believe next month I will be able to do 40!"
question: What problems does Chen Xingzhu have according to the passage?
options: He is also not good at math. He is also not good at PE. He is also not good at sit-ups. He is also not good at PE entrance exam.